1. Field of the Invention
The present invention relates to an electrode-coating glass composition, a coating for forming an electrode-coating glass, and a plasma display panel using the same and its manufacturing method.
2. Description of Related Art
In recent years, there has been an increasing demand for large-screen high-quality television. Conventionally used CRTs (cathode-ray tubes) are better in resolution and image quality than plasma displays and liquid crystal displays, but are not suitable for a 40-inch or larger screen in terms of depth and weight. Although liquid crystal displays have excellent characteristics of low power consumption and a low drive voltage, they have a limitation in their screen size and viewing angle. On the other hand, plasma displays can achieve both a large screen and a small depth, and products on the order of 60 inches already have been developed.
FIG. 1 is a perspective view showing a configuration of an AC type plasma display panel. For facilitating an understanding, FIG. 1 shows a front plate and a back plate of the plasma display panel separately (in an unintegrated manner).
In FIG. 1, numeral 1 denotes a front plate, and numeral 2 denotes a back plate. The front plate 1 is constituted by providing display electrodes 12 and black stripes 13 on a front substrate 11, further providing a dielectric glass layer 14 that coats these display electrodes 12 and black stripes 13, and then providing a dielectric protective layer 15 thereon. The front substrate 11 is formed of, for example, borosilicate sodium glass or lead glass that is produced by a float process. The display electrodes 12 are belt-like electrodes, which are formed of, for example, ITO (indium tin oxide) and a silver (Ag) film or a chromium (Cr)—copper (Cu)—chromium (Cr) layered film. The dielectric glass layer 14 is formed using glass powder having a mean particle size of 0.1 to 20 μm, and functions as a dielectric layer of a capacitor. The dielectric protective layer 15 is formed of, for example, magnesium oxide (MgO). On the other hand, the back plate 2 is constituted by providing a plurality of address electrodes 22 on a back substrate 21, further providing a dielectric glass layer 23 that coats the address electrodes 22, and then providing barriers 24 and phosphor layers 25 thereon. The back substrate 21 is formed of glass like the front substrate 11. The address electrodes 22 are belt-like electrodes that are perpendicular to the display electrodes 12 of the front plate 1, and formed of an Ag film, a Cr—Cu—Cr layered film or the like. The barriers 24 separate the plurality of belt-like address electrodes 22 from each other so as to form a discharge space. In other words, the space between adjacent barriers serves as the discharge space in which a discharge gas is to be sealed. The phosphor layers 25 are formed from above the address electrodes 22 toward side surfaces of the barriers 24. In order to allow a color display, the phosphor layers 25 are arranged between the barriers 24 such that phosphor layers 25b, 25b and 25c of three colors that are formed of materials emitting visible light of red (R), green (G) and blue (B) are provided sequentially.
In such a plasma display panel, the dielectric glass layer 14 provided in the front plate 1 needs to have a high dielectric withstand voltage. The properties of this dielectric withstand voltage vary considerably depending on a surface condition and a film defect of the dielectric glass layer 14.
A conventionally known method for forming this dielectric glass layer 14 includes applying a paste containing glass powder, a solvent, a resin serving as a binder (in the following, referred to as a binder resin), a plasticizer and a dispersant to the display electrodes 12 of the front plate 1 by screen printing, spraying, blade coating or die coating, followed by drying and then firing.
However, in such conventional method and materials for forming the dielectric glass layer 14 that coats the display electrodes 12, since many air bubbles remain in the film, the dielectric glass layer 14 has a low transparency and is susceptible to a dielectric breakdown. Accordingly, it has been difficult to form the dielectric glass layer 14 having a high transparency and a high dielectric withstand voltage.